2 answers

You can see the flows installed on a table of a specific switch with http://<controller-ip>:8181/restconf/config/opendaylight-inventory:nodes/node/<node-id>/table/<table-number> link.</table-number></node-id></controller-ip>

The XML requests obey the syntax of YANG if I'm not mistaken.
In this) link you can see the structure of the links to send the requests.
On this one you can see the yang modules where is specified the format of the xml or json requests.

You can also check the ODL documentation that has some example on matching parameters and actions.
Links below: